CA-108915: Deprecate mpathHBA so dev_loss_tmo can be configured by DMP

SM calls the script /opt/xensource/sm/mpathHBA if a host has at least one
multipathed HBA SR. The script mpathHBA goes through all fc-ports and specifies
dev_loss_tmo (and the deprecated variant lpfc_nodev_tmo) as MPATH_TIMEOUT=30s.
This is not good because some users need to modify this timeout value in order
to accommodate controller failover events.

In recent versions of DM Multipath dev_loss_tmo can be configured as a
configuration option in /etc/multipath.conf. This commit removes
/opt/xensource/sm/mpathHBA so DMP can set the dev_loss_tmo-value that customers
define in multipath.conf.